<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="../react18/react.development.js"></script>
    <script src="../react18/react-dom.development.js"></script>
    <script src="../react18/babel.min.js"></script>
</head>

<body>
    <button id="btn">修改vDOM,并重新渲染</button>
    <div id="app"></div>
    <script type="text/babel">
        /* 
          diff算法的比较
            Diff算法比较只会在同层级进行, 不会跨层级比较,如果当前层级不一致则直接替换
            diff算法在某个层级比较一致的话,会进入层级内部再次比较,默认按照DOM书写顺序进行比较
    
            伪代码:
            旧的虚拟DOM
              <li key="001">html <input type="text" /></li>
              <li key="002">css <input type="text" /></li>
              <li key="003">js <input type="text" /></li>
    
            新的虚拟DOM
              <li key="004">react <input type="text" /></li>
              <li key="001">html <input type="text" /></li>
              <li key="002">css <input type="text" /></li>
              <li key="003">js <input type="text" /></li>
              
    
        
        
        
        
        */
        const arr = [
            { id: "001", con: "html" },
            { id: "002", con: "css" },
            { id: "003", con: "js" },
        ]
        const vDOM = (
            <ul>
                {
                    arr.map(item => (<li key={item.id}>{item.con} <input type="text" /></li>))
                }
            </ul>
        )
        const root = ReactDOM.createRoot(document.getElementById('app'));
        root.render(vDOM)


        //给按钮绑定点击事件,修改数据 然后重新得到新的vDOM 重新渲染
        const oBtn = document.getElementById('btn');
        let i = 0;
        oBtn.onclick = function () {
            arr.unshift({ id: Date.now(), con: "react" + i++ });
            const vDOM = (
                <ul>
                    {
                        arr.map(item => (<li key={item.id}>{item.con} <input type="text" /></li>))
                    }
                </ul>
            )
            root.render(vDOM)
        }
    </script>
</body>

</html>